Composition of matter



Patented Feb. 6, 1934 i-TED STAT-as PATENT OFFICE Elmer H. Hyde andFloyd D. Hager, Pittsburgh,

to Tar Products pany, Inc., a corporation of Delaware No Drawing.Application July 15, 1930 Serial No. 468,201

7 Claims. (Cl. 167-45) The product of the present invention may com--prise the total distillate from coal tar which is driven 01f therefromup to a temperature of substantially 800 F. to 1,000 F. It is preferredhowever to use the total distillate from soft or hard pitch, andpreferably from hard pitch upto the formation of coke.

- obtained from pitch when coking the latter in a suitable retort orby-product coke oven is called pitch oil.

The total distillate from soft pitch includes the higher boiling cuts ofcreosote oil which cuts may be used but which are not as effective aspitch oil. By soft and hard pitches we mean that pitches having meltingpoints below 100 to 110 C. (cube in air method) are soft and pitcheshaving melting points above those temperatures are hard.

The best resultsare obtained when a large percentage or all of the pitchoil fraction is used. This fraction contains such organic compounds ofhigh molecular weight (over 200) as chrysene,

' pyrene, retene, pycene, truxene, chrysogene, and others includingcompounds containing nitrogen and oxygen. Compounds may be presentwhichhave a molecular weight. of 200 and above. A mixture of these substancesis more desirable than any of them singly. In other words, the

40 entire pitch oil fraction is more desirable than portions thereof.

If desired, the heavier more viscous fractions may be diluted with asuitable diluent such as a volatile solvent, or water when the oil hasbeen properly emulsified. The volatile solvents may be ether, benzene,carbon bisulphide, carbon tetrachloride, solvent naphtha, or the like,or mixtures of two or more of these. The lighter fractions of coal tar,as for instance those occurring in the aforesaid total istillate of tar.may also serve as diluents.

other liquids, such as water gas tar distillate,-

The total distillate tar distillate may be any well known fractions ofwater, gas tar, obtained for instance as distillates having a boilingpoint range of from about 100 C. to about 385 C. Theproper fluidity mayalso be obtained by heating without the; addition of a diluent or otherliquid.

The following examples of compositions to be used for the purpose setforth are given by way of illustration:

Example 1.20% by weight of pitchv oil or heavy creosote oil arehomogenized with. about u by weight of water gas tar distillate having-a boiling point range preferably of C. to

the use of any suitable emulsifying agent such I as soap, sulphonatedoil, clay, bentonite, or the like. The emulsion should preferably bemade i as concentrated as possible and diluted to the required degree atthe place where used. An emulsifying agent which gives good results andwhich is preferred is one containing water soluble salts of sulphonatedpitch oil prepared as set forth in a copending application of F. D.l-Iager. Serial No. 471,095, filed July 26, 1930.

Such an emulsion, as made in the concentrated form, contains about 66.6%by weight of pitch oil, 8% of emulsifyi agent, and 25.3% of water. Thefinal product should be slightly alkaline. It may be diluted with therequired amount of water before use. The amount of water necessary isgoverned, in a large measure, by the mode of application.

Another emulsifying. agent which has been found useful in emulsions ofpitch oil, is liquid sodium resinate prepared from black liquor obtainedin the treating of wood pulp described in the copending application ofE. H. Hyde filed May 2'1, 1930, Serial No. 456,293.

Any well known method of applying the com-. position of the presentinvention may be employed. The most eflective method is to project thematerial over the desired area in the form of a fine spray or mist. i

We claim as our invention:

1. A composition of matter, for use in preventingthe growth ofvegetation and in the destruction of weeds, comprising a mixture of allof the distillates of coal tar which are driven off therefrom up to atemperature of substantially from 800 F. to 1,000 F.

2. A composition of matter, for use in preventing the growth ofvegetation and in the destruction of weeds, comprising a mixture of allof the distillates of coal tar pitch which are driven of! therefrom upto a temperature of substantially !rom8 00 F. to 1,000 F.

3. A composition of matter, for use in preventing the growth ofvegetation and in the destrucing the growth of vegetation and in thedestruc tion of weeds, comprising a distillate irom coal tar pitch, inthe form of an emulsion with water weights of. substantially and aiiovand an emulsifying agent, the said disti1latec9n+5 taining compounds"having" moleculai" weights over 200.

6. A composition of matter, for use in preventing the growth ofvegetation and in the destruction of weeds, comprising a mixture ofcompounds contained in the pitch oil fraction 01' coal tar, the said,compoundsv having lnolecular 7. A composition of matter, for use' inpreventing the growth of vegetation and in the destruction of weeds,comprising a mixture of a diluent and compounds contained in pitch oiltraction lar weights of substantially 200 and above.

ELMER H. HYDE. FLOYD D. HAGER.

of coal 'tar,- the said compounds having molecu-

